Mixed reality is a technology that allows virtual imagery to be mixed with a real world physical environment in a display. Systems for mixed reality may include, for example, see through head mounted displays or smart phones with built in cameras. Such systems typically include processing units which provide the imagery under the control of one or more applications.
Emotions have an important influence in human lives, and can influence psychological and social behavior. Humans communicate their emotional state constantly through a variety of verbal and non-verbal behaviors. These expressions can include explicit signals such as smiles and frowns, laughing and crying, to subtle variations in speech rhythm, facial expressions, eye focus or body posture. The range of non-verbal and nonverbal behaviors that transmit information about personality and emotion is large. Emotional arousal affects a number of easily observed behaviors, including speech speed and amplitude, the size and speed of gestures, and some aspects of facial expression and posture. Extensive research has been conducted to correlate observable behaviors with detectable emotional states.